QUANTIFICATION OF AORTIC-STENOSIS IN MECHANICALLY VENTILATED PATIENTSUSING MULTIPLANE TRANSESOPHAGEAL DOPPLER-ECHOCARDIOGRAPHY

Study objectives: To evaluate the feasibility and accuracy of multipla ne transesophageal Doppler echocardiographic assessment of the severit y of aortic stenosis in mechanically ventilated patients using modifie d transgastral views of the left ventricular outflow tract and the aor tic valve. Design: A prospective study comparing the results of transe sophageal echocardiography (TEE) with transthoracic echocardiography ( TTE) and cardiac catheterization. Setting: A university hospital. Pati ents: Twenty-eight American Society of Anesthesiologists class III and IV patients with aortic stenosis undergoing elective cardiac surgery for valve replacement. Interventions: Intubated and mechanically venti lated patients with aortic stenosis undergoing cardiac surgery for val ve replacement were studied by multiplane transesophageal Doppler echo cardiography to determine transvalvular pressure gradients (Bernoulli formula) and valve areas (continuity equation). These findings were co mpared with the respective preoperative data from TTE and cardiac cath eterization. Measurements and results: In 25 of 28 patients (89%), ade quate transgastral Doppler recordings of the aortic jet could be obtai ned. The TEE measurements correlated well with the respective data obt ained by TTE (maximal pressure gradient: r=0.93, p<0.0001, mean differ ence=5.9+/-5.8 mm Hg [mean+/-SD]; mean pressure gradient: r=0.91, p<0. 0001, mean difference=5.4+/- 4.6 mm Bg; aortic valve area: r=0.97, p<0 .0001, mean difference=0.07+/-0.05 cm(2)) and cardiac catheterization (n=16) (maximal vs peak-to-peak pressure gradient: r=0.84, p<0.0001, m ean r=0.80, p<0.0002, mean difference=9.7+/-5.9 mm Hg; aortic valve ar ea: r=0.84, p<0.0001, mean difference=0.1+/-0.08 cm(2)), Conclusion: M ultiplane transesophageal Doppler echocardiography offers an alternati ve approach for assessing the severity of aortic stenosis in mechanica lly ventilated patients in whom difference=10.9+/-8.8 mm Hg; mean pres sure gradient: conventional TTE is not feasible.